1. Field of the Invention
The invention relates to a watertight protective device for holding a measuring or display device, and more particular to a protective device having a protective housing, the inside contour of which is shaped so conform with an the outer dimensions of a contained measuring or display device.
2. Description of the Related Art
Protective devices serve to hold measuring or display devices in a water- and dust-tight fashion, with the operation of the device not being adversely affected by the protective device. Known protective devices consist of flexible transparent protective sheaths with a pouch design that can be sealed to make them water- and dust-tight. Operation of a measuring or display device placed in the protective sheath is retained because of the flexibility of the sheath. To guarantee flexibility, such protective sheaths are made of a relatively thin plastic material so that the lifetime of such sheaths is limited in the frequently harsh operating conditions to which measuring devices are subjected. Under extreme operating conditions, there is frequently the risk that the measuring or display device will be damaged by external application of force since the thin sheath cannot withstand such external forces.
Another disadvantage of known protective sheaths is that with even minor damage to the protective sheath surface water tightness may no be longer guaranteed. In addition, the protective sheath may prevent the measuring device from accurately measuring the quantity to be measured, since the measuring device is wholly contained within the protective sheath.
Accordingly, it is an object of this invention to provide a protective device which is water-tight and dust-tight, and which will protect a contained display or measuring device against an externally applied force.
According to one aspect of the invention, a protective device includes a protective housing made from a dimensionally stable material. The inside contour of the protective housing is shaped to conform with the outer dimensions of the display or measuring device so that there is essentially zero play between the protective device and the contained device. Additionally, the protective housing may have an operating area that is transparent and yields elastically to enable operation of the contained device.
By providing a protective device of this nature, the dimensionally unstable protective sheaths previously used may be replaced by a dimensionally stable housing in which, as the result of a suitable choice of materials, the operating and display elements of the inserted measuring or display device remain visible through the housing wall and can also be operated. The essentially zero-play accommodation of the measuring or display device offers optimum protection against external applications of force. The protective device so designed is largely unaffected by objects, especially those with sharp edges, that would have damaged the surface of conventional protective sheaths, since the wall thickness is much greater than the wall thickness of the conventional protective sheaths. Thus, the lifetime of the protective device is extended.
In one embodiment, the inside contour of the protective device is shaped to conform with the contours of the measuring or display device it is designed to contain. By doing this, the outer dimensions of the protective device may be minimized while still performing the sealing and protecting functions.
To facilitate insertion and removal of the measuring or display device, the housing is preferable formed of an upper part and a lower part which may be releasably connected with each other. The lower housing part can be connected with the upper housing part by a circumferential groove formed on either the upper or lower housing part and a circumferential rib formed on the other housing part. In operation, the rib engages the groove to join the upper housing part and the lower housing part. In this manner, a reliable seal may be formed between the two housing parts by using an elastically flexible material with a rib that is at least slightly larger than the groove. The sealing effect of the connection between the upper housing part and lower housing part can be additionally increased by providing sealing lips on the groove and/or rib.
Optionally, the upper housing part may be connected to the lower housing part by a hinge, for example a film hinge, which can prevent one of the two parts from being lost. Other types of hinges, such as pin hinges or living hinges may also be used.
To ensure complete operation of the measuring or display device placed in the protective device, an operating area may be provided on the protective device behind which the operating and/or display area of the measuring or display device is located. In one embodiment, the housing portion that serves as the operating area of the protective housing has a reduced wall thickness. In this manner, it is possible for a user to operate buttons on the measuring or display device, as long as the operating area is capable of sufficient elastic deformation by finger pressure. From a manufacturing standpoint, it is advantageous to form the operating area integral with the protective housing, and from the same material.
For example, transparent soft PVC can be used as the material for making the protective housing described above. When this material is used, a protective device can be obtained that is transparent not only in the operating area but everywhere. In addition, thermoplastic elastomers (TPE) or thermoplastic polyurethanes (TPU) can be used to make the protective housing.
Another embodiment provides for providing recesses, preferably on the side facing away from the operating area, that can serve to fasten the protective housing, including the measuring or display device accommodated therein, to a matching mount. In order to achieve greater resistance to twisting of the protective device and hence improved handling ability, at least one reinforcing strip may be provided. The reinforcing strip may be made of the same material as the protective housing or different material. The reinforcing strip offers greater protection for the measuring or display device located in the protective device against outside forces.
In order to connect a measuring or display device placed in the protective device with a measuring sensor or other peripheral device for example, an opening is provided in the protective device through which a plug can be guided in a watertight fashion and then connected with the measuring or display device.
The vicinity of the opening can be easily sealed by matching the shape and size of the opening with the shape and size of the plug, so that the protective housing abuts the plug in the area of the opening over its entire surface and therefore forms a watertight seal. Optionally, a sealing lip may be located in the opening to provide a linear contact all the way around the plug that has been inserted or against the housing of the measuring or display device, thus producing a watertight seal. A lip of this nature is advantageous in that the plug can be inserted through the opening by the application of a low force.
A stand may be provided on the housing and connected to the housing by a hinge so that the hinge may be moved in and out (similar to a picture frame). In this manner, the stand may enable the measuring device, contained in the protective housing, to stand upright on a desk or other surface. Recesses may be provided on the housing and used to fasten the protective housing to a mount or to a rotatable stand.
An area of reduced wall thickness is preferably provided on the protective housing on a side that is opposite a removal opening. This area can be deformed by a user in order to push the inserted measuring or display device toward the removal opening for removal. The measuring and display device advantageously abuts the area of reduced wall thickness at a pusher.
According to another aspect of the invention, a protective device includes a protective housing made of a dimensionally stable material. The protective housing has a lower housing part and an upper housing part which can be releasably connected with one another. A measuring/display device which has a display and/or an interaction field and a circumferential seal can be received in the protective housing. At least one of the lower housing part and the upper housing part includes a flexible operating area which is sealed against the respective housing part so that a user can view and/or interact with the display or interaction field. The circumferential seal engages with an inside wall of the lower and/or upper housing part to seal a space between at least a portion of the measuring/display device and the respective lower or upper housing part against the ambient.
Embodiments of the invention may include one or more of the following features. The circumferential seal may be integrally formed with the measuring/display device or may be formed by a circumferential groove disposed on the measuring/display device and an O-ring which engages with the circumferential groove of the measuring/display device. The inside wall of the respective housing part may include a circumferential wall groove which can engage with the circumferential seal. The circumferential wall groove can be in the form of an upper wall groove portion disposed on the upper housing part and a lower wall groove portion disposed on the lower housing part. The lower and/or upper housing part may include a projection or a resilient section, which retains the measuring/display device at a predetermined location inside the protective housing when the lower housing part and the upper housing part are closed.
Further features and advantages of the present invention will be apparent from the following description of certain embodiments and from the claims.